Hydrochloric Acid → Fenamole

Participants

Reaction Conditions

Reaction Steps

To a warm (50° C.), stirred solution of N'-phenylhydrazinecarboximidamide monohydroiodide (86.4 g, 0.31 mol) in water (300 mL) was added in one portion 70% nitric acid (2.80 mL, 0.0435 mol) followed by dropwise addition of a solution of silver nitrate (52.66 g, 0.3100 mol) in water (70 mL). The resulting suspension was allowed to cool over 30 minutes. To the still warm (+35° C.) mixture was added concentrated hydrochloric acid (3.6 mL). The solids were filtered off and washed with hot water (60 mL). The filtrate and washings were combined and acidified with concentrated hydrochloric acid (22.3 mL). The mixture was chilled (+5° C.) and stirred while a solution of sodium nitrite (21.46 g, 0.3110 mol) in water (70 mL) was added dropwise. The temperature of the solution was kept below 8° C. by controlling the addition rate. The solution was stirred for 15 minutes. To the mixture was added powdered sodium carbonate (36.14 g, 0.341 mol) in small portions to avoid excessive foaming. The resulting precipitate was stirred for 2 days. The solids were filtered off, washed with water (3×20 mL), and dried under house vacuum/air bleed at 45° C.; yield 38.77 g (77.4%), mp=158.5°-159.5° C.

Provenance & Evidence